import os
import shutil
import subprocess


def ffmpeg_suitability(path):
    try:
        version = subprocess.run([path, "-version"], check=True,
                                 capture_output=True).stdout.decode("utf-8")
    except:
        return 0
    score = 0
    # rough layout of the importance of various features
    simple_criterion = [("libvpx", 20), ("264", 10), ("265", 3),
                        ("svtav1", 5), ("libopus", 1)]
    for criterion in simple_criterion:
        if version.find(criterion[0]) >= 0:
            score += criterion[1]
    # obtain rough compile year from copyright information
    copyright_index = version.find('2000-2')
    if copyright_index >= 0:
        copyright_year = version[copyright_index + 6:copyright_index + 9]
        if copyright_year.isnumeric():
            score += int(copyright_year)
    return score

def get_ffmpeg_path():
    if "VHS_FORCE_FFMPEG_PATH" in os.environ:
        ffmpeg_path = os.environ.get("VHS_FORCE_FFMPEG_PATH")
    else:
        ffmpeg_paths = []
        try:
            from imageio_ffmpeg import get_ffmpeg_exe

            imageio_ffmpeg_path = get_ffmpeg_exe()
            ffmpeg_paths.append(imageio_ffmpeg_path)
        except:
            if "VHS_USE_IMAGEIO_FFMPEG" in os.environ:
                raise

        if "VHS_USE_IMAGEIO_FFMPEG" in os.environ:
            ffmpeg_path = imageio_ffmpeg_path
        else:
            system_ffmpeg = shutil.which("ffmpeg")
            if system_ffmpeg is not None:
                ffmpeg_paths.append(system_ffmpeg)
            if os.path.isfile("ffmpeg"):
                ffmpeg_paths.append(os.path.abspath("ffmpeg"))
            if os.path.isfile("ffmpeg.exe"):
                ffmpeg_paths.append(os.path.abspath("ffmpeg.exe"))
            if len(ffmpeg_paths) == 0:

                ffmpeg_path = None
            elif len(ffmpeg_paths) == 1:
                # Evaluation of suitability isn't required, can take sole option
                # to reduce startup time
                ffmpeg_path = ffmpeg_paths[0]
            else:
                ffmpeg_path = max(ffmpeg_paths, key=ffmpeg_suitability)

    return ffmpeg_path

